Updates to Left 4 Dead 2 have been released. The updates will be applied automatically when your Steam client is restarted. The major changes include:

Left 4 Dead 2

New Mutation: Bleed Out Versus

Tank speed is no longer reduced when on fire

Fixed team votes passing without a majority from both teams Fixed a bug where the add-on list could become unresponsive to mouse input Protected against some console commands that could be used to lag or crash servers